From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750786AbWFEJBz (ORCPT ); Mon, 5 Jun 2006 05:01:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750814AbWFEJBy (ORCPT ); Mon, 5 Jun 2006 05:01:54 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:21907 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S1750786AbWFEJBy (ORCPT ); Mon, 5 Jun 2006 05:01:54 -0400 Date: Mon, 5 Jun 2006 11:01:19 +0200 From: Ingo Molnar To: Andrew Morton Cc: Benjamin Herrenschmidt , linux-kernel@vger.kernel.org, tglx@linutronix.de, torvalds@osdl.org Subject: Re: [RFC][PATCH] request_irq(...,SA_BOOTMEM); Message-ID: <20060605090119.GA849@elte.hu> References: <1149486009.8543.42.camel@localhost.localdomain> <1149491309.8543.54.camel@localhost.localdomain> <20060605003127.fc1ea37a.akpm@osdl.org> <1149493691.8543.57.camel@localhost.localdomain> <20060605012405.ac17f918.akpm@osdl.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060605012405.ac17f918.akpm@osdl.org> User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: -3.1 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-3.1 required=5.9 tests=ALL_TRUSTED,AWL,BAYES_50 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts 0.0 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.5005] 0.2 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Andrew Morton wrote: > And yes, the mutex code will (with debug enabled) unconditionally > enable interrupts. ppc64 tends to oops when this happens, in the > timer handler (so it'll be intermittent...) hm, i sent a patch to fix that, long time ago. > But looking at > work-around-ppc64-bootup-bug-by-making-mutex-debugging-save-restore-irqs.patch > I realise I don't understand it. We only go into the irq-enabling > code in the case of contention, and there cannot be contention in this > case? in the debug case we go into the 'slowpath' all the time - so that we can do the debug checks under the mutex lock. if we get real contention then we have a might_sleep() check that will catch that. i'd suggest to push work-around-ppc64-bootup-bug-by-making-mutex-debugging-save-restore-irqs.patch upstream - i thought we agreed that while it's a bit hacky and slows the mutex code down a bit, it's not practical right now to forbid uncontended mutex_lock() in early init code? Ingo